Nearly a half-a-million Iraqis have been displaced from their homes in the country's western al-Anbar province due to the foreign-backed terror violence, the UN High Commissioner for Refugees (UNHCR) says.

“The full scale of the displacement from this ... conflict is unknown, as the Iraqi authorities have had to suspend registration over the past month because of insecurity," said UNHCR spokesman Adrian Edwards at a press conference in the Swiss city of Geneva on Friday, adding, "UNHCR believes the current figure is now close to 480,000."

The agency has managed to gather only 12 percent of the $26.4 million (19 million euro) needed to tackle the crisis in Anbar since it started its work there back in March.

Displacement in Anbar increased after Takfiri militants intentionally breached a dam, which flooded the area and forced some 72,000 people from their homes, Edwards said.

The move has made Iraqis’ access to clean water difficult, noted the UNHCR spokesman, adding, "Local officials say 28 tanker truckloads of potable water are being delivered to the area every day, but this is only meeting 50 percent of needs."

"We urgently need to ramp up our response which is difficult for three reasons: We have deteriorating security in Anbar hindering access to people in need, the displaced are spread out across much of the country, and donor support is lacking."

The violence in Anbar broke out on December 30, 2013, when the army removed an anti-government protest camp in Ramadi. Authorities said the camp was used as “headquarters for the leadership of al-Qaeda.” The bloodshed later spread to nearby Fallujah.

The security forces supported by Sunni tribesmen have been battling the militants since then.